Devices that rely on the interplay between electricity and magnetism underlie much of modern electronics. Relatively recently, researchers have begun to develop and implement such devices that take advantage of quantum mechanical magnetoresistance effects, such as giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR). GMR and TMR principles regard how the resistance of a thin film structure that includes alternating layers of ferromagnetic and non-magnetic layers depends upon whether the ferromagnetic layers are in a parallel or antiparallel alignment. For example, magnetoresistive random-access memory (MRAM) is a technology that is being developed that typically utilizes TMR phenomena in providing for alternative random-access memory (RAM) devices. In a typical MRAM bit, data is stored in a magnetic polarization within an arrangement that includes two ferromagnetic plates separated by an insulating layer—this arrangement is conventionally referred to as a magnetic tunnel junction (MTJ). One of the ferromagnetic plates (the fixed layer) is permanently set to a particular polarization, while the other ferromagnetic plate (the free layer) can have its magnetic polarization altered. Generally, the MRAM bit can be written to by manipulating the magnetic polarization of the free layer such that it is either parallel or antiparallel with the polarization of the fixed layer; and the bit can be read by measuring its resistance, since the resistance of the bit will depend on whether the polarizations are in a parallel or antiparallel alignment.
MRAM technologies initially exhibited a number of deficiencies. In particular, they tended to be inefficient since they required a relatively large current to manipulate the magnetic polarization of the bit's free layer. Consequently, adjunct technologies were implemented to mitigate these deficiencies. For example, spin-transfer torque MRAM (STT-MRAM) is a variant of the base MRAM technology whereby the magnetizing current constitutes spin-aligned electrons that are used to directly torque the domains. Additionally, Thermal Assisted Switching MRAM (TAS-MRAM) is yet another variant of MRAM technology whereby the MTJs are heated during the write phase; the heating of the MTJs reduces the current required to polarize the free layer.
Nonetheless, in spite of these advances to MRAM technology and in spite of the many potential advantages that MRAM technology offers, it has yet to achieve widespread adoption. Accordingly, there exists a need to develop more effective electromagnetic configurations that implement magnetoresistance principles such that they can be made to be more viable.